To prevent this, turbochargers can be provided with an air recirculation valve (also referred to as an overrun air recirculation valve) which, beyond a certain underpressure, opens a connecting duct in a pressure-controlled manner by means of a spring-loaded valve element, which connecting duct recirculates the air to the compressor inlet. It is thereby possible for the rotational speed of the turbocharger to remain at a high level, and for charge pressure to be immediately available again in the event of a subsequent acceleration process.
In known turbochargers having an air recirculation valve of said type, the compressor housing, which has a valve flange for the air recirculation valve, is produced primarily by gravity die casting or sand casting. It is also known to produce such valve housings by pressure die casting, wherein it is however necessary here for a plurality of molded parts to be joined together, since the geometries of the individual molded parts must be selected such that said molded parts can be demolded in the pressure-die-casting process. However, this increases the design expenditure and therefore the production costs.